Question

The following events all occur during the electron transport chain and ATP synthesis in a respiring mitochondrion. Which answer places these events in the correct order they occur?

A: Reduction of cytochrome c

B: Reduction of O2

C. Oxidation of NADH

D. Proton movement from IMS to matrix

Answers:

C-A-B-D

A-B-C-D

C-A-D-B

C-B-A-D

D-C-A-B

Answer 1

Option C-B-A-D

Oxidation of NADH Reduction of O2Reduction of cytochromeProton movement from IMS to matrix

Reduced electron carriers from other steps of cellular respiration transfer their electrons tp molecules near the begining of the transport chain.

As electrons are passed down the chain they move from a higher to a lower energy level releasing energy . some of the energy is used to pump H+ ions , moving them out of the matrix and into the intermembrane space.

At the end of electron transport chain , electrons are transfered to molecular oxygen , which splits in half and takes up H+ to form water.

As H+ ions flow down their gradient and back into the matrix they pass through an enzyme called ATP synthase which harness the flow of protons to synthesize ATP